An urn contains three red balls and four blue balls. Draw two balls at random from the urn, without replacement. Compute the expected number of red balls in your sample. (Round your answer to four decimal places.)

Answers

Answer 1

Step-by-step explanation:

in total we have 3+4 = 7 balls.

when we draw the first ball, the probability to draw a red ball is 3/7, and a blue ball 4/7.

when we draw the second ball, we have now only 6 balls in total.

the probabilty to draw a red back now depends also on the result of the first draw.

if the first ball was already red, then we have only a chance now of 2 out of 6.

if the first ball was blue, then we have now a chance of 3 out of 6.

so, the probably to draw at least 1 red ball in 2 draws is the probability of drawing one on the first draw plus the probability of drawing one on the second :

1 - probability to see 2 blue balls

1 - 4/7 × 3/6 = 1 - 12/42 = 30/42 = 0.714285714...

the expected number of red balls in 2 draws is

1 red in first red in first red in second

but not second and second but not first

1×(3/7 × 4/6) + 2×(3/7 × 2/6) + 1×(4/7 × 3/6) = 12/42 + 12/42 + 12/42 = 36/42 = 6/7 = 0.857142857 ≈ 0.8571


Related Questions

Convert 70°F to Celsius using the following formula: °C = 5/9 (°F-32).
Round your ANSWER to the nearest degree.
Select one:

a. 126°C
b. 21°C
c. 158°C
d. 53°C

Answers

Answer:

21

Step-by-step explanation:

(use you calculator)

method of bidmas should be used

5/9 (70-32) substitute the F with 70

5/9 (38) calculate the brackets first

0.555 (38) next, calculate 5/9

0.555×38=21.09 or 21.1111... finally, multiply

hope this helps

Put 70 instead of F degree, and 70-32=38 then
38x5=190
190:9=21.1111111
The answer is approximately 21 degree celcius
You can choose the answer B

Solve 2x2 – 6x + 10 = 0 by completing the square.

A)

x = 3∕2 + i , x = 3∕2 – i

B)

x = 3 + i, x = 3 – i

C)

x = 3∕2 + 1∕2 i, x = 3∕2 – 1∕2i

D)

x = 3 + i, x = 3 – i

Answers

Answer:

The answer is C.)

Step-by-step explanation:

I hope its help Please let me know.

So when you are adding fractions how do you know when you need to simplify the numbers and how do you simplify?

Answers

Let's look at an example.

We'll add the fractions 1/6 and 1/8

Before we can add, the denominators must be the same.

To get the denominators to be the same, we can...

multiply top and bottom of 1/6 by 8 to get 8/48multiply top and bottom of 1/8 by 6 to get 6/48

At this point, both fractions involve the denominator 48. We can add the fractions like so

8/48  + 6/48 = (8+6)/48 = 14/48

Add the numerators while keeping the denominator the same the entire time.

The last step is to reduce if possible. In this case, we can reduce. This is because 14 and 48 have the factor 2 in common. Divide each part by 2.

14/2 = 748/2 = 24

The fraction 14/48 reduces to 7/24

Overall, 1/6 + 1/8 = 7/24

One kilometre is about 0.62 miles. It is 12 kilometres from Noah's house to the
ice skating rink. About how many miles is it from Noah's house to the ice
skating rink?


u'll get extra points if u answer guys!! pls help!!!!!

Answers

Answer:

7.44miles

Step-by-step explanation:

1km = 0.62miles

12km will be ; 0.62 × 12

= 7.44miles

I NEED HELP WITH THESE
I am pretty sure of my answers, so I just need someone to double check. Explanation is not needed because I know how to solve it, just needs to be checked. You can put one it you want.

Answers

Answer:

(b) 500 km (b) 6 seconds

Step-by-step explanation:

1.

The semi-major axis length is √47196900 = 6870 km. That distance from the center of the Earth means the satellite is ...

  6780 -6370 = 500 . . . km

from the surface of the Earth.

The satellite is a maximum of 500 km from the Earth.

(It is a minimum of 250 km from Earth.)

__

2.

The equation has a zero at t=6. When the car's velocity is zero, it is at a complete stop.

The car comes to a complete stop when time is 6 seconds.

(The car is still being accelerated, so it doesn't stay stopped.)

__

I prefer a graphing calculator for a quick solution. You can also solve this equation algebraically.

  0 = 0.5t^2 -10.5t +45 . . . . t when v(t) = 0

  t^2 -21t +90 = 0 . . . . . . . multiply by 2

  (t -6)(t -15) = 0 . . . . . . . . factor

  t = 6 or t = 15 . . . . . . . only t=6 is in the domain of the function

Write -37.75 as a mixed number.​

Answers

Answer:

[tex]-37\frac{3}{4}[/tex]

Step-by-step explanation:

0.75 is equivalent to three quarters, or (3/4).

3/4 would be the fraction. -37 would be the whole number.

[tex]-37.75 = \boxed{-37\frac{3}{4}}[/tex]

Hope this helps.

Answer:

- 37 3/4

Step-by-step explanation:

Solve the equation. -10=2y

Answers

Answer:

y=-5

Step-by-step explanation:

-10/2=2y/2

-5=y

y=-5

Answer:

y = - 5

Step-by-step explanation:

You have yo divided the numbers

Cancel terms that are in both the numerator and denominator

Move the variable to the left

1 minute is equal to 60 seconds. How many seconds are in 3 minutes, 37 seconds?

Answers

Answer:

217 Seconds.

Step-by-step explanation:

The answer is 217 seconds because 60x3+37=217.

An angle of 90° measures (___) Pi radians.

An angle of -pi/5 radians measures ____?

°.

Answers

[tex]\huge \bf༆ Answer ༄[/tex]

Conversion from degree to radian ~

[tex] \boxed{ \sf{ \frac{\pi}{180} \times \theta }}[/tex]

[tex] \sf \dfrac{\pi}{180 } \times 90[/tex]

[tex] \sf \dfrac{\pi}{2} \: \: rad[/tex]

Conversion from radians to degree ~

[tex] \boxed{ \sf{ \frac{180}{\pi} \times \theta}}[/tex]

[tex] \sf \dfrac{180}{\pi} \times - \dfrac{ \pi}{5} [/tex]

[tex] \sf - 36 \degree[/tex]

The required measures of the angles in radians and degree are given as  π/2 radians and -36° respectively.

What are the angle?

Orientation of the one line with respect to the horizontal or other respective line is known as a measure of orientation and this measure is known as the angle.

here,
An angle of 90° measures
in radians,
angle = π/180 × Ф
angle = π/180 × 90 = π/2 radians

Similarly,
An angle of -pi/5 radians
in degrees,
angle = 180 / π × -π/5
angle = -36°

Thus, the required measures of the angles in radians and degree are given as  π/2 radians and -36° respectively.

Learn more about Angles here:

https://brainly.com/question/13954458

#SPJ2

Find a polynomial f(x) of degree 4 that has the following zeros. -7, 0, 1, 6
leave your answer in factored form.

please help! its my exam study guide and i need to finish it! ​

Answers

[tex]\begin{cases} x=-7\implies &x+7=0\\ x=0\implies &x=0\\ x=1\implies &x-1=0\\ x=6\implies &x-6=0 \end{cases}\qquad \implies (x+7)(x)(x-1)(x-6)=\stackrel{y}{0} \\\\\\ (x+7)(x)\stackrel{using~\mathbb{FOIL}}{(x^2-7x+6)}=0\implies (x^2+7x)(x^2-7x+6)=0[/tex]

[tex]\begin{array}{llll} x^2-7x+6\\ \qquad \times ~x^2\\\cline{1-1} x^4-7x^3+6x^2 \end{array}\qquad +\qquad \begin{array}{llll} x^2-7x+6\\ \qquad \times ~7x\\\cline{1-1} 7x^3-49x^2+42x \end{array} \\\\\\ (x^4-7x^3+6x^2)+(7x^3-49x^2+42x)=0 \\\\[-0.35em] ~\dotfill\\\\ ~\hfill x^4-43x^2+42x=y~\hfill[/tex]

PLZ HELP ASAP I NEED A ANSWER!!
Which characteristics did early Japanese, Chinese, and Korean civilizations share?

They were friendly nations that shared culture and customs.
They were nations at war that shared a common religion.
They were neighboring countries that shared a common history.
They were countries with dissimilar culture and customs.

Answers

Answer:

When looking at the feudal system, which is a notable difference between Japanese Samurai and European Knights? Japanese Samurai were not considered part of the higher class. European Knights were not part of the military. Japanese Samurai were highly educated.

Step-by-step explanation:

hey yo how is this math

What is 50 million + 32 hundred thousands + 41 hundred

Answers

Answer:

82041000

Step-by-step explanation:

50,000,000 + 32,000,000 + 41,000

A group of friends were working on a student film that had a budget of $1300. They used $546 of their budget on props. What percentage of their total budget did they spend on props?

Answers

To find percentage: divide the given value by the total and multiply by 100

546/1300 x 100 = 42%

Which is the equation of a circle with a radius of 6 and a center of (3,-1)?
(x - 3)2 + (y+1)2 = 36
(x+3)2 + (y - 1)2 = 36
(x+3)2 + (y - 1)2 = 6
(x-3)2 + (y+ 1)2 = 6

Answers

Answer:

358

Step-by-step explanation:

576

Can someone help me? Will mark brainiest :)

Answers

the anser is 2 cuz i sad so, and i was droped don te stars as a lil kid ÆÆÆÆÆÆÆÆÆÆÆÆÆÆÆÆÆ

LAST ATTEMPT !! MARKING AS BRAINIEST!!

Answers

I can’t see the picture very well

The dimensions of a trapezoid are halved.
a) How will the area be affected?
b) If the area of the original trapezoid is 28 cm?, then what will the area of the smaller
trapezoid be?
Draw or add images here

Answers

Answer:

  a) area will be 1/4 of the original

  b) 7 cm²

Step-by-step explanation:

a)

Consider the equation for the area of a trapezoid:

  A = 1/2(b1 +b2)h

Now, halve each of the dimensions:

  A' = 1/2((1/2)b1 +(1/2)b2)((1/2)h)

  A' = (1/4)(1/2(b1 +b2)h) = 1/4A

The area is multiplied by the square of the scale factor: (1/2)² = 1/4.

__

b)

The area of the smaller trapezoid will be ...

  A' = 1/4A = (1/4)(28 cm²) = 7 cm²

someone please please please answer!!!

Answers

Answer:

7.07 or "5 × square root of 3"

Step-by-step explanation:

in an isosceles triangle, the longest side is equal to "x × square root of 3" while the other two sides equal x. hope this helps

(3x(3)+9X(2)+27X)/3X

Answers

3x | 3x^3+9x^2+27x |x^2+3x+9x

- 3x^3

-------

9x^2

- 9x^2

---------

27x

- 27x

--------

0

Answer:

x^2 + 3x + 9x

Hope you could get an idea from here.

Doubt clarification - use comment section.

#6) Find the value of x. Be sure to show your work. ​

Answers

The answer is x=70

My work below in the picture

Twice a number is 46 less than 4 times the number. Find the number.

Answers

Answer:

23

Step-by-step explanation:

let the number be n then twice the number is 2n and 4 times the number is 4n

Then

2n = 4n - 46 ( subtract 4n from both sides )

- 2n = - 46 ( divide both sides by - 2 )

n = 23

The number is 23

Answer:

34.5

Step-by-step explanation:

23 x 2 = 46 less than 4 times = 11.5

46 - 11.5 = 34.5

HELPPPP ASAPPPPPPPPPPPP

Answers

Answer:

C

Step-by-step explanation:

9
11 (a) Grapes cost £2 per kilogram.
Calculate the cost of 380g of grapes.

Answers

Answer:

£0.76

Step-by-step explanation:

1kilogram = 1000grams

1000g of grapes costs £2

380g costs = (380 × 2)/ 1000

760/1000 = £0.76

The sum of three terms in AP is 15. If the first two terms are each decreased by 1 and the last is increased by 1 then the resulting terms are in GP. find the numbers.​

Answers

Answer:

3, 5, ,7 or 9, 5, 1

Step-by-step explanation:

Let the three terms in AP be a - d, a & a + d

where a = First term and d = Common difference.

Condition 1: sum of three terms in AP is 15.

a - d + a + a + d = 15

3a = 15

a = 15/3

a = 5

Condition 2: When first two terms are each decreased by 1 and the last is increased by 1 then new terms so obtained will be as follows:

a - d - 1, a - 1, a + d + 1

These terms are in G.P.

[tex] {(a - 1)}^{2} = (a - d - 1)(a + d + 1) \\ \\ {(5 - 1)}^{2} = (5 - d - 1)(5 + d + 1) \\ \\ {(4)}^{2} = (4 - d)(6 + d) \\ \\ 16 = 24 + 4d - 6d - {d}^{2} \\ \\ 0 = 8 - 2d - {d}^{2} \\ \\ {d}^{2} + 2d - 8 = 0 \\ \\ {d}^{2} + 4d - 2d - 8 = 0 \\ \\ d(d + 4) - 2(d + 4) = 0 \\ \\ (d + 4)(d - 2) = 0 \\ \\ d + 4 = 0 \: \: or \: \: d - 2 = 0 \\ \\ d = - 4 \: \: or \: \: d = 2 \\ \\ when \: d = - 4 \\ \\ a - d = 5 - ( - 4) = 9 \\ a = 5 \\ a + d = 5 - 4 = 1 \\ \\ when \: d = 2 \\ a - d = 5 - 2 = 3 \\ a = 5 \\ a + d = 5 + 2 = 7 \\ \\ thus \: three \: terms \: in \: AP \: are: \\9, \: 5, \: 1 \: \: or \: \: 3, \: 5, \: 7[/tex]

Aarón rides his bike away from home at a constant speed he stops at the park for a while before riding back home at a constant speed

Answers

Answer:

Step-by-step explanation: This is the answer

As a hurricane approaches, the air temperature changes −7.8°F every hour.

Which value represents the change in air temperature over 1.25 hours?


−9.75°F

−9.05°F

−6.55°F

−6.24°F

Answers

The change in air temperature over 1.25 hours is -9.75°F

A linear equation is in the form:

y = mx + b;

where y, x are variables,  m is the rate of change and b is the initial value of y.

As a hurricane approaches, the air temperature changes −7.8°F every hour. The amount of change after 1.25 hours is:

Change = −7.8°F every hour * 1.25 hours

Change = -9.75°F

Therefore the change in air temperature over 1.25 hours is -9.75°F

Find out more on linear equation at: https://brainly.com/question/14323743

Work out the area of the triangle.

Answers

Answer:

120

Step-by-step explanation:

10*24=240

240/2=120

The base of a triangle is 4 ft more than the height. If the area is 30ft2, find the base and the height.

Answers

Answer:

Base = 10 ft. and the height = 6.

Step-by-step explanation:

Area of triangle = 1/2bh

base is 4 + h  ⇔  base = 4 + h

height = h

Using the formula for the area of triangle substitute into the formula the given facts.

A = 1/2bh

30 = 1/2(4 + h) (h)

30 = 1/2(4h + h²)     Multiply both sides by 2

60 = 4h + h²

-60 =           -60      Add -60 to both sides

0 = h²+ 4h -60        

(h + 10)(h - 6) = 0      Factor

h + 10 = 0    h - 6 =0

h = -10         h = 6

reject any negative number and use the positive answer for h.

So h = 6      and the base = 4 + 6 ; base = 10

2.5 x 10^3 times what number is equal to 5 x 10^6?

Answers

Answer:

2

Step-by-step explanation:

Answer:

2000.

Step-by-step explanation:

First, calculate both sides. 2.5x10^3= 2500 and 5x10^6=5000000

then divide 5000000/2500 = 2000

Solve using substitution,

y = -3
x + 3y = -6
Please help

Answers

Answer:

x=3

Step-by-step explanation:

x+3(-3)=-6

x-9=-6

  +9 +9

x=3

Answer:

x=3 y=-3

Step-by-step explanation:

solve for x then substitute x in the original problem then solve for y

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